1. Field of the Invention
The invention relates to an antenna for a submarine vessel, which antenna is arranged in a floating body and is connected to the submarine vessel via a connecting element which transmits the information received by the antenna.
2. Description of the Prior Art
For radio communication with a submerged submarine vessel only extremely low frequencies can be employed, as is known, because the damping by the seawater is too high at higher frequencies. In addition, the penetration depth for frequencies in the range from 10 to 20 kHz is only approximately 10 to 20 meters depending on the salinity and temperature. Furthermore, at such low frequencies the screening effect of the hull of the vessel is so small that interference from the interior of the vessel can reach the exterior and is superimposed on the desired signal as noise.
Therefore use is made of antennas which are remote from the vessel, which are located at a sufficient distance from the noise zone radiated by the submarine vessel and which also enable the submarine vessel to submerge to a greater depth, the remote antenna being maintained underneath the water surface within range of the penetration depth of the frequencies to be received. Such an antenna in the form of a trailing buoy of the kind mentioned in the opening paragraph is mentioned in the paper by Dupont-Nivet "Telecommunications avec les sous-marines" in Defense nationale = F = 32 (1976) 1, Jan., pages 63-74. Such a buoy antenna, however, is comparatively large and hydrodynamically unfavourable, which limits the manoeuvrability of the submarine vessel and permits ready detection of the buoy antenna by sonar. Furthermore, in general such a buoy antenna cannot be maintained at a substantially constant depth at varying speeds of the vessel without the use of an active control system.